This next stage was really stressful for me because I’d read loads about the process of making foam latex prosthetics from various sources and there were so many different takes on the subject I didn’t really know where to start. Of course Dick Smith’s text from the course was the most comprehensive but also had so much detail about the do’s and don’ts and ways to cope with potential problems that I actually felt more apprehensive. The book that was particularly useful was Special Makeup Effects For Stage And Screen by Debreceni which has a section that explains the process thoroughly without going into an overwhelming amount of detail. If you want to read the entire process in complete detail you need to read this book because I can’t explain it as effectively or at such length in this post.
I didn’t manage to take photos during this whole procedure because I was up to my eyes in latex for most of the time, (I’m a messy worker), but I did take photos of all the final pieces.
I think I managed eventually to take the plunge by taking the basic points and making notes from these two main sources and just have a go at it without thinking too much about what could go wrong. This isn’t to say I didn’t have to do a lot of preparation and buy a fair amount of materials prior to actually making the prosthetics though.
Firstly I had to buy the four agent components needed to create the foam latex prosthetic. I managed to find a kit by The Monster Makers from a very useful and interesting site http://mouldlife.co.uk/ which included all the agents and a mold release. It’s fairly costly to aquire these materials but luckily I only needed a relatively small amount to make enough for all the pieces for this project so have plently left. This would depend though on the size of the pieces you need and if any re-runs have to be done due to mistakes.
Another very important piece of equipment I need was a mixer/beater. Because of the alarming amount of ways the foam can be affected, I decided to go for the closest model of mixer that Dick Smith recommends, hoping that his ways to deal with potential problems would apply most closely. I managed to find a Kenwood Chef (quite a vintage model) from eBay which ended up working really well, although I did have change the mixing bowl from the large glass one that came with the mixer to a smaller plastic one with straight sides as Dick recommended.
The size and design of the mixing vessel has a big effect on the foam latex as the process relies on the rate of the loss of ammonia during the beating. The rate of loss is altered by the surface area and the temperature, (amongst other things), so one batch mixed in a glass broad bowl would likely be quite different to one mixed in a straight sided, more narrow, plastic vessel. Of course you can use whatever you prefe,r or that works for you, but DS states on several occasion how important it is to record every detail of each batch so you can go back and see which are successful. I’ll describe this in more detail later in the post. The one I decided on was a plastic tupperware bowl, 6 inches in diameter with straight sides although I actually bought them in a ‘nest’ collection, very cheaply, so I had a selection of sizes to choose from. This too was fairly successful although with not being manufactured for the Kenwood Chef it didn’t fit the base so I had to hold it while it was beating which wasn’t ideal. I made a note of that too because that could affect the outcome.
I bought some digital scales, (instead of a triple beam balance that is recommended by DS), just for ease, to measure out the agents as accurately as possible. These were found on Amazon relatively cheaply also but can be found anywhere.
A stopwatch is another essential piece of equipment as each stage of the beating of the latex needs to timed very accurately. I just used my phone for this but will get a proper stopwatch for future projects.
There are other factors that can affect the batch such as temp and humidity so I ‘aquired’ one of those little digital weather systems from my Dad, (who’s slightly obsessed with that kind of thing), that includes all of those elements so I could record all the necessary factors in the studio at the time of making the foam latex.
The final major piece of equipment is a measuring stick that is used to record the increasing volume of the foam as it rises. I made my own from a thin piece of dowling. I measured out the initial volume of all the components mixed together and marked this on the stick by cutting a notch into it. I reset the scales and added the same volume and marked the second volume the same way and so on … This is essential to be able to monitor and record the rise of the foam.
I made some record sheets on Excel so that I could print or photocopy more when I needed them but any method would do as long as the info is recorded. These include every aspect of the process, following advice from DS again, and I’ll list them now but describe in more detail when I get into actually carrying out the procedure.
The categories are; JOB, DATE, TEMP, HUMIDITY, CURING AGENT, FOAMING AGENT, ADDITIVES, GELLING AGENT, MIXER, MIXING (TIME,VOL,SPEED,) MIX TIME (REACH VOL,REFINING,MIX GEL AGENT), COLOUR, GEL TIME (START,FINISH), BAKING (HOURS,TIME IN, TIME OUT), OVEN TEMP, RESULTS, MOLDS, MOLD MATERIALS, SEPARATORS, NOTES.
The kit I bought contains these four components to form the foam latex;
Latex Base – Usually a high ammonia, high solids natural latex. Smells really strongly of ammonia and will have a pH of over 10. (pH is a scale that measures relative acidity with i being most acidic to 14 most alkaline. pH 7 is neutral).
Foaming Agent – Bonds as a soap to the cells of the latex which lowers the surface tension and allows it to froth and break down more easily.
Curing Agent – Contains sulphur to help vulcanize (strengthen and add elasticity) to the latex.
Gelling Agent – Creates a reaction that changes the foam from a liquid to a solid.
Before I began the process of running the foam latex I needed to prep my molds. It’s essential that the molds are bone dry because when heated, any water molecules left in the porous plaster can create steam pockets between the plaster and foam that can distort the appliance. To prevent this I put them in the oven for an hour or so until they were uniformly white and allowed them to cool thoroughly before applying a very thin layer of mold release all over the inside surfaces with an old soft paintbrush making sure I got it into all the nooks and crannies.
Running the Foam Latex
I made sure I had all the necessary equipment and nearby so felt organised as possible. As I’d mentioned before I’d made my own set of instructions from the two main sources to try to simplify things a little because the more I read the more bogged down I got in the detail. It definitely helped me a lot and I knew I had all the extra info to hand to sort out any potential problems as I went along if I needed them.
A basic batch is roughly 150g Latex Base, 30g Foamimg Agent, 15g Curing Agent and 14g Gelling Agent
(The optimal conditions are 69-72 F (20.6-22 C) and 45-55 % Humidity)
On this day in the studio, the temp was 18.1 C and humidity was 58% so not ideal. I first weighed out the agents directly into the mixing bowl on the scales after zeroing of course, and again after every volume was added. I started with the smallest volume and worked upwards as this way it’s possible to rectify problems if I added too much, or too little by accident. I also measured out the gelling agent separately in a plastic cup as this is added at a later stage. (At this point if I was adding any pigment I would’ve put a few drops into the gelling agent and mixed it through. DS suggests using an eye dropper for accuracy).
Beating to Volume – (2.5 – 5 mins)
For the first run it’s difficult to know when the rise is approaching the right level until you get more confident. It’s a good idea according to DS again that you stop at the end of every 30 secs – minute (mixer and timer) and measure and record the volume so you can get a feel for it. I did this every 30 secs because it rose quite quickly. Only took about 2 mins 30 secs to reach 5x volume which was the volume I was going for, again on advice based on what I needed. It’s possible to increase the volume by spinning the bowl rapidly if necessary. Usually takes between 2 and 1/2 mins to 5 mins.
Refining – (5+ mins)
This is needed to get rid of any larger air bubbles and usually takes a minimum of 5 minutes. It can take more than 5 mins but only if large bubbles remain. If the foam is refined for too long, the ammonia lost can cause the final product to be too fragile. I restarted the timer before I started to refine the foam and mixed it at setting 3 for 5 mins until the foam appeared fine and smooth, (no large air bubbles).
Adding Gelling Agent – (2+ mins)
The gelling agent needs to be added and dispersed as quickly as possible without introducing any air into the foam. After the refining stage I reset the timer and restarted the mixer again at the same speed 3 as I poured in the gelling agent as quickly and carefully as possible. It’s important to aim away from the wall of the bowl so all the liquid is incorporated into the foam. (Can use a spatula to remove the foam from the walls if necessary). Usually takes 2+ mins to ensure the agent is mixed through thoroughly. Once this is done the foam is ready to transfer to the prepared molds.
Loading The Mold – There are two major ways to load the molds, pouring and injecting. For molds like mine that are no bigger than a face the pouring method is fine. (The injection method is used for larger molds and is a very different procedure that I will learn at a later stage). For my molds though I used a spoon to transfer the foam into the negative side of each mold, (because it’s concave), especially the nose mold, because it’s important to ensure the foam gets right to the end of the tip, again to avoid air bubbles ruining the prosthetic. There is a time limit on this of course because the foam is starting to gel during the whole procedure. I took care to make sure all the molds were filled properly in all the details, though it’s surprising how little you actually need because the prosthetic pieces were intentionally sculpted thinly to look as realistic as possible and also so they hopefully will move quite well when the character/actor makes expressions when wearing them. When I was sure they were ok I placed the positive side of the mold on top and pushed together slowly and carefully, allowing the excess to squeeze out the sides (which is why you sculpt the flashing), until you can feel the two sides connect. I cleaned the sides a bit and then they were ready to be put into the oven.
Curing the Foam – When I read the different artists’ methods of curing the foam latex I realised that it comes down to preference based on their personal experience so again I just decided on one particular way and thought would be able to judge from the results. Again there are many factors that can alter the outcome but I took a middle line from the sources and just hoped for the best.
Apparently basic small appliances usually take around 2 – 2.5 hrs to fully cure, when baked at around 185 F. You can load the oven cold and allow it to heat with molds in, but I let it heat to 180 F first. Actually the dial on the oven had no relevance to the actual temp so was glad I have an oven thermometer to make sure the internal oven temp was accurate. The prosthetic pieces were spaced as evenly as possible in the oven to allow the air to circulate and took about 2hrs to fully cure. I allowed the molds to cool in the oven afterwards which is better for them as they’re able to gently change temp which helps prevent cracking.
De-Molding – When the molds were still warm they were taken from the oven as it’s easier to de-mold the appliances in this state than if allowed to cool completely. I used a blunt, wooden sculpting tool to pry the two pieces of the mold apart, so I didn’t damage the pieces. With each appliance, as with the gelatin in the previous post, I brushed talc as I was gently easing the foam latex pieces away from the mold to prevent the edges sticking.
Once they were free they need to be gently washed in warm water with a couple of drops of washing up liquid to remove any residual sulphur from the curing agent. The process needs to be repeated until there is no visible residue in the water and the soap rinsed out. The water was gently squeezed out and then pressed between two towels and then left on the positive of the mold to dry properly and retain it’s shape.
These are the photos of the finished pieces …
This last photo shows all the trimmed pieces on the face cast together to demonstrate how the make-up will hopefully look when they’re applied to the skin.